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A primary goal of community ecologists is to understand the processes underlying the spatiotemporal patterns of species distribution. Understanding the dispersal process is of great interest in ecology because it is related to several mechanisms driving community structure. We investigated the mobility of dung beetles using mark-release-recapture technique, and tested the usefulness of the current recommendation for interaction distance between baited pitfall traps in the Brazilian Atlantic Forest. We found differences in mean movement rate between Scarabaeinae species, and between species with different sets of ecological traits. Large-diurnal-tunneler species showed greater mobility than did both large-nocturnal tunneler and roller species. Our results suggest that, based on the analyses of the whole community or the species with the highest number of recaptured individuals, the minimum distance of 50 m between pairs of baited pitfall traps proposed roughly 10 years ago is inadequate. Dung beetle species with different sets of ecological traits may differ in their dispersal ability, so we suggest a new minimum distance of 100 m between pairs of traps to minimize interference between baited pitfall traps for sampling copronecrophagous Scarabaeinae dung beetles.

Dung beetles of the Scarabaeinae subfamily are present in temperate and tropical ecosystems. Some species of these insects feed on millipede carcasses. The objective of this study was to determine the attraction of Canthon vazquezae to volatiles released by Messicobolus magnificus. The bioassay was performed using a Y-glass tube olfactometer. Canthon vazquezae was significantly attracted to dead M. magnificus, as well as stressed and wounded individuals. In contrast, unstressed M. magnificus did not attract C. vazquezae. The volatiles released by M. magnificus in stressed, wounded, and dead states were analyzed by gas chromatography coupled to mass spectrometry (CG-MS). Six compounds were tentatively identified as 2-methyl-p-benzoquinone, trimethyl-p-benzoquinone, 1,2,4-trimethoxybenzene, 2-methyl hydroquinone, 2,5-dimethoxythiophenol, and 3,4-dimethoxyphenol. Some of these compounds have been identified as attractants to other coleopterans.

Background We used Illumina paired-end sequencing to isolate and characterize microsatellites of Canthon cyanellus , a Neotropical roller dung beetle, encompassing several lineages within its distribution range. Methods and results We examined C. cyanellus specimens collected at eight different localities in Mexico (two or three specimens per locality). We initially performed amplification tests with 16 loci, but two of which were unsuccessful. The 14 remaining microsatellites were polymorphic, with 2–16 alleles each. The expected and observed heterozygosity ranged from 0.11 to 0.76 and from 0.20 to 0.78, respectively. Conclusions These microsatellites will help to assess structure at the population and lineage levels, identify zones of potential hybridization between lineages, and draw a more precise geographic delimitation of C. cyanellus lineages.

Subspecies is a debated taxonomic rank that, in some cases, could indicate that a speciation process is taking place. Studying the degree of co-occurrence among subspecies along environmental gradients may help to determine its taxonomic status. In this study, we explore the distribution of two subspecies of Canthon rutilans along spatio-temporal and temperature gradients in the Atlantic Forest of southern Brazil in order to reinforce their current subspecies status or to support their consideration as two different species. A yearly survey conducted along an elevational transect (from 250 m to 1630 m) shows that there is no spatio-temporal overlap between the two taxa. We collected 899 individuals of Canthon rutilans cyanescens and 29 individuals of Canthon rutilans rutilans. C. rutilans cyanescens can be found at 250 m (all year except in June), 430 m (August to April), and 840 m (September to April) in elevation, and when the air temperature oscillates from 15.3 °C to 24.0 °C. C. rutilans rutilans can be found at 1360 m (October to February), 1630 m (January) in elevation, and when the air temperature oscillates from 14.4 °C to 18.6 °C. Furthermore, local temperature data taken during the survey indicates that both subspecies also have a limited overlap in their thermal response curves. All these results suggest that these two taxa could be considered as two different species with dissimilar physiological and ecological requirements probably as a consequence of temperature-mediated divergent adaptation. Further molecular data can confirm or reject this supposition in the near future.

Theory predicts that asymmetry between contenders influences their ability to defend resources. More recently, some theoretical approaches have also examined the circumstances that might promote sharing of the disputed resources. We tested these hypotheses in males of the ball roller beetle Canthon cyanellus cyanellus. Males fight for possession of a food ball, which is a vital resource used for nesting. We evaluated the role of food resource ownership, body size and reproductive status on the outcome of contests (win, lose or share) between males that rolled a food ball (owners or finders) either alone or with a female partner, when faced with male intruders (or joiners). Large owners of a food ball had a higher probability of victory than small intruders, and small owners had a high probability of losing when faced with large intruders. The reproductive status of both contenders also influenced their chances of winning: previously mated owners of a food ball had a higher probability of winning than virgin owners. Males of a similar size tended to split the food ball, thereby sharing the resource. Our results suggest that competitors may adjust the intensity of their aggression depending at least on their own resource holding power (RHP), the value of the resource in dispute and perhaps even the RHP of their opponents. Sharing the food ball emerges as a fresh solution between similarly matched contestants.

We described, for the first time, a case of predation of a non-arthropod species by a dung beetle species. Canthon chalybaeus Blanchard, 1843 kills healthy individuals of the terrestrial snail Bulimulus apodemetes (D’Orbigny, 1835) showing an evident pattern of physical aggressiveness in the attacks using the dentate clypeus and the anterior tibiae. The description of this predatory behaviour was complemented with the analysis of the chemical secretions of the pygidial glands of C . chalybaeus , highlighting those main chemical compounds that, due to their potential toxicity, could contribute to death of the snail. We observed a high frequency of predatory interactions reinforcing the idea that predation in dung beetles is not accidental and although it is opportunistic it involves a series of behavioural sophistications that suggest an evolutionary pattern within Deltochilini that should not only be better studied from a behavioural point of view but also phylogenetically.

Forest conversion into lands for different uses is a widespread practice in tropical and subtropical regions. Such anthropogenic disturbance drastically modifies environmental conditions and availability of resources for species (ecological niche). While many species usually disappear or become rare, other (resilient species) persist in the disturbed areas, being subject to new and often stressful conditions (ecological filters). The issue of whether human-driven habitat modifications induce phenotypic changes in resilient organisms at the intraspecific level has been poorly studied thus far. In this study, we used the neotropical dung beetle Canthon quinquemaculatus to test the hypothesis that the conversion of native forest into open cattle pastures can induce phenotypic differentiation in the functional morphology of resilient species. Sexual dimorphism and year of collection were simultaneously evaluated as potential sources of intraspecific variation in the measured morphological traits. We measured several functional traits related to thermal niche, burrowing capacity and food resource manipulation, including body size and shape and the size of the anterior leg and its constitutive parts. We found significant morphological differentiation between habitats (native forest vs. cattle pasture), sexes and years in terms of multi- and single-trait comparisons. Individuals from cattle pastures were smaller and less spherical (because of lower body thickness) compared to individuals from native forest. Males were larger with bigger anterior tibia and femur while females were more spherical. The phenotypic differences observed between individuals from native and converted habitats could be attributed to plasticity and/or contemporary (adaptive) evolution. From an ecological viewpoint, this study shows that habitat disturbance may affect morphological variation and functional diversity at the intraspecific level which may in turn influence ecosystem functions that dung beetles perform (i.e. dung burial).

Fil: Munevar Lozano, Ana Katerinne. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina

The fragmentation and degradation of otherwise continuous natural landscapes pose serious threats to the health of animal populations, consequently impairing their fitness and survival. While most fragmentation ecology studies focus on habitat remnants embedded withinn terrestrial matrices, the effects of true insularization remains poorly understood. Land‐bridge islands created by major dams leads to habitat loss and fragmentation, negatively affecting terrestrial biodiversity. To assess the effects of insularization, we conducted a study on the key aspects of dung beetle physiological condition and body size throughout the Balbina Hydroelectric Reservoir located in the Central Amazon. We assessed these traits at the population and assemblage levels, collecting dung beetles from both forest islands and continuous forest areas while analyzing various landscape variables. We show that landscapes with higher forest cover positively affected dung beetle body size. Interestingly, dung beetle responses to insularization were species‐dependent; larger islands tended to host larger individuals of Deltochilum aspericole, while in Canthon triangularis, smaller islands showed larger body sizes. However, individuals from the mainland were larger than those from the islands. Moreover, the proportion of closed‐canopy forest in the landscapes also impacted physiological attributes. It negatively affected the body size of Deltochilum aspericole and the lipid mass of Dichotomius boreus, but positively affected the lipid mass of Canthon triangularis. These findings contribute to a better understanding of how habitat fragmentation in aquatic matrices affects the size structure and physiology of insect assemblages. This is essential in formulating effective conservation strategies for preserving biodiversity loss in tropical forest regions and mitigating the consequences of hydropower infrastructure. Insular landscapes restrain dung beetles physiological condition. Dung beetles inhabiting riverine islands are smaller than their conspecifics from mainland. Insularization showed contrasting ecological responses, which differed depending on dung beetle species.

A biodiversity and distribution analysis of the beetle families Bolboceratidae and Geotrupidae, and the subfamily Scarabaeinae (Scarabaeidae) of Honduras is presented for the first time. The checklist contains 98 species: two Bolboceratidae, one Geotrupidae, and 95 Scarabaeinae. The fauna of Honduras includes two genera of Bolboceratidae, one genus of Geotrupidae, and 22 of Scarabaeinae. Onthophagus is the most speciose genus, with 21 species, followed by Canthon (10 species) and Copris (9 species). Valid names and synonyms are provided. First country records, notes on presently recognized species, distribution maps, and biodiversity comparisons are included, and nomenclatural problems associated with species in question are discussed. Phanaeus lempira Kohlmann, Solís and Rivera, sp. nov. (Coleoptera: Scarabaeidae) is described as a new species. Canthon sallei Harold, 1863 and Canthon spinosus Harold, 1863 are reinstated as valid species. Canthon cyanellus LeConte, 1859 does not contain any subspecies. Two new synonymies are established: Canthon cyanellus violetae Halffter, 1961, syn. nov. of Canthon sallei Harold, 1863; Canthon speciosus Harold, 1868, syn. nov. of Canthon spinosus Harold, 1863.